Anti-government protests in Ukraine took a violent turn Monday after the government enacted laws restricting assembly rights, with angry demonstrators erecting barricades in the street to block off the government quarter.

Protestors attacked police with sticks and firecrackers in Kiev on Sunday, and by Monday they were using pipes, cobblestones and firebombs as the police struck back with tear gas and water cannons in the freezing temperatures, the Associated Press reports. Protestors put up barricades in streets leading to the government quarter as the prospect of talks between Ukrainian President Viktor Yanukovich and demonstrators appeared unclear.

Over 200 people including demonstrators and police were wounded in the clashes and 20 people have been arrested, authorities said, just days after the government set legal restrictions on protests.

U.S. National Security Council spokeswoman Caitlin Hayden said that Washington was urging “all sides to immediately de-escalate the situation.”

The old Soviet bloc nation is being yanked on both ends by two big geopolitical influences, the European Union and Russia, with Putin’s government luring the financially strapped Ukraine with large aid packages and the EU hoping to bring Ukraine into its fold. Anti-government protests began in Kiev in November when Yunkovich rejected an EU partnership in favor of maintaining ties with Russia.